Problem 7.120 Challenge

กำหนดให้ \(r = 1.50 m, ω_{0} = 0 rad/s, v = 25.0 m/s\)

และ \(θ = 2.25(2π) = 4.50π rad\)

จาก \(ω^{2}= \omega _{0}^{2} + 2\alpha \cdot \theta \)

\(\alpha =\frac{(\frac{v}{r})^{2} - \omega _{0}^{2}}{2\theta }\)

\(\alpha =\frac{v^{2}}{2\theta r^{2}}\)

\(\alpha = 9.82 rad/s^{2} \;\blacksquare\)

จาก \(θ = \frac{(\omega  + \omega _{0})t}{2}\)

\(t =\frac{2\theta }{(\omega  + \omega _{0})}\)

\(t =\frac{2\theta }{(\frac{v}{r}) + \omega _{0}}\)

\(t = 1.70 s \;\blacksquare\)